What is Java?

The first thing we need to understand to get started is exactly what is Java? When someone says Java, what are they talking about?

Well, Java is a programming language, but Java is also a runtime environment. It's both of those things. So, when we think about the programming language, it has things like the syntax, the data types, control flow, like looping and conditional statements and being object‑oriented, right, doing inheritance, and so forth. And then runtime, of course, must support those things, but it also provides things like configuration, security, a threading model, input/output, that sort of thing. So, when someone says Java, they could be referring to a programming language or the runtime environment or the whole thing. Now in general, the runtime environment someone is talking about when they just say Java is often referred to as Java Standard Edition. Right, that's kind of the basic Java environment. But it also provides other environments that derive from that, Enterprise Edition, Java Micro Edition, and Java FX. So those are all either supersets or subsets of this main thing, which is just the Java Standard Edition. But the thing that's neat about Java, it's so flexible that there are even run times that are not tied to the Java one produced by Oracle. Right, Android is kind of most well-known one. Android provides a very different runtime than the standard Java run times from Oracle. The thing is, though, that all those environments support effectively the same Java programming language, right. So that one language equips us the work in all those different places.